I Opened a Café in Another World. - Volume 2, Chapter 5: Interviews are hard.

A mecha otaku is reincarnated into another world as Ernesti Echevalier (Eru). In this world there exist huge humanoid weapons known as Silhouette Knight. Dreaming of piloting those robots, Eru, with childhood friends, Archid Walter and Adeltrud Walter: together they will aim to become a Knight Runner, pilot of Silhoutte Knight.

Xiao Ze, who was dedicated to the people and vowed to become a generation of Ming Jun, accidentally fell on a little lady.
The little lady was born beautiful and lovable.
So Xiao Ze accepted his life and got the name of fear.

ps:
①The male protagonist has no concubine, and he is dedicated to serving the country.

- Description from novelbuddy

Ruins stretched across the landscape in the apocalypse after the nuclear war.

There was a prominent old martial arts family which in the hundred years would give birth only to males, never a girl. Finally, one day, a girl was born. She was a tassel blower among ten thousand green groves. Ultimately, she turned into an agile and brave tomboy!

There was also an imperial descendant who his old father had six princesses. His father was just short of a son to inherit the throne. Finally, one day, he got a bastard son who was his youngest child. With countless spoiling, in the end that son was brought up into a universally unmatched egomania!

“Zhen as the nation’s number one beauty, as the nation only first class figure, obviously needs to have a professional bodyguard constantly at our side for protection. That will be you, the iron-willed female King Kong pretending to be a little eunuch.”

- Description from Novelupdates